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  <div class="section" id="using-nullbooleanfield">
<h1>Using NullBooleanField<a class="headerlink" href="#using-nullbooleanfield" title="Permalink to this headline">¶</a></h1>
<p>To make a boolean field that accepts <code class="docutils literal notranslate"><span class="pre">NULL</span></code> values in addition to <code class="docutils literal notranslate"><span class="pre">true</span></code> and <code class="docutils literal notranslate"><span class="pre">false</span></code>, use a <code class="docutils literal notranslate"><span class="pre">BooleanField</span></code> with the option <code class="docutils literal notranslate"><span class="pre">null=True</span></code>, rather than a <code class="docutils literal notranslate"><span class="pre">NullBooleanField</span></code>.</p>
<p>The <code class="docutils literal notranslate"><span class="pre">null=True</span></code> option for <code class="docutils literal notranslate"><span class="pre">BooleanField</span></code> was introduced in Django 2.1. <code class="docutils literal notranslate"><span class="pre">NullBooleanField</span></code> was deprecated in Django 3.1, and is removed in Django 4.0.</p>
<div class="section" id="anti-pattern">
<h2>Anti-pattern<a class="headerlink" href="#anti-pattern" title="Permalink to this headline">¶</a></h2>
<p>The following model uses a <code class="docutils literal notranslate"><span class="pre">NullBooleanField</span></code>.</p>
<div class="highlight-python notranslate"><div class="highlight"><pre><span></span><span class="kn">from</span> <span class="nn">django.db</span> <span class="kn">import</span> <span class="n">models</span>

<span class="k">class</span> <span class="nc">Person</span><span class="p">(</span><span class="n">models</span><span class="o">.</span><span class="n">Model</span><span class="p">):</span>
    <span class="n">first_name</span> <span class="o">=</span> <span class="n">models</span><span class="o">.</span><span class="n">CharField</span><span class="p">(</span><span class="n">max_length</span><span class="o">=</span><span class="mi">30</span><span class="p">)</span>
    <span class="n">last_name</span> <span class="o">=</span> <span class="n">models</span><span class="o">.</span><span class="n">CharField</span><span class="p">(</span><span class="n">max_length</span><span class="o">=</span><span class="mi">30</span><span class="p">)</span>
    <span class="n">activated</span> <span class="o">=</span> <span class="n">models</span><span class="o">.</span><span class="n">NullBooleanField</span><span class="p">()</span>
</pre></div>
</div>
</div>
<div class="section" id="best-practice">
<h2>Best practice<a class="headerlink" href="#best-practice" title="Permalink to this headline">¶</a></h2>
<p>Instead, use a <code class="docutils literal notranslate"><span class="pre">BooleanField</span></code> with the option <code class="docutils literal notranslate"><span class="pre">null=True</span></code>.</p>
<div class="highlight-python notranslate"><div class="highlight"><pre><span></span><span class="kn">from</span> <span class="nn">django.db</span> <span class="kn">import</span> <span class="n">models</span>

<span class="k">class</span> <span class="nc">Person</span><span class="p">(</span><span class="n">models</span><span class="o">.</span><span class="n">Model</span><span class="p">):</span>
    <span class="n">first_name</span> <span class="o">=</span> <span class="n">models</span><span class="o">.</span><span class="n">CharField</span><span class="p">(</span><span class="n">max_length</span><span class="o">=</span><span class="mi">30</span><span class="p">)</span>
    <span class="n">last_name</span> <span class="o">=</span> <span class="n">models</span><span class="o">.</span><span class="n">CharField</span><span class="p">(</span><span class="n">max_length</span><span class="o">=</span><span class="mi">30</span><span class="p">)</span>
    <span class="n">activated</span> <span class="o">=</span> <span class="n">models</span><span class="o">.</span><span class="n">BooleanField</span><span class="p">(</span><span class="n">null</span><span class="o">=</span><span class="kc">True</span><span class="p">)</span>
</pre></div>
</div>
</div>
<div class="section" id="reference">
<h2>Reference<a class="headerlink" href="#reference" title="Permalink to this headline">¶</a></h2>
<ul class="simple">
<li><p><a class="reference external" href="https://docs.djangoproject.com/en/3.1/ref/models/fields/#booleanfield">Django documentation - Model field reference: BooleanField</a></p></li>
<li><p><a class="reference external" href="https://docs.djangoproject.com/en/3.1/ref/models/fields/#nullbooleanfield">Django documentation - Model field reference: NullBooleanField</a></p></li>
</ul>
</div>
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